Among the conventionally-known types of front vehicle body structures are one where a load applied or input to a bumper beam is transmitted to front side frames, upper members, lower members, etc. by way of extension members or impact absorbing sections. Front vehicle body structures of that type are designed in accordance with a size and usage of the vehicle and in consideration of desired impact absorbing performance and impact transmitting performance. Examples of the front vehicle body structures of that type include one disclosed in Japanese Patent Application Laid-Open Publication No. 2005-112173 (hereinafter referred to as “patent literature 1”) in which the impact absorbing sections are provided on front end portions of the left and right front side frames, and one disclosed in Japanese Patent Application Laid-Open Publication No. 2007-190964 (hereinafter referred to as “patent literature 2”) in which the impact absorbing sections are provided on front end portions of both the front side frames and the lower frames.
More specifically, in the front vehicle body structure disclosed in patent literature 1, the extension member or impact absorbing section, provided on each of the left and right sides of the vehicle body, extends to the neighborhood of the rear side of the bumper so that an impact input to the bumper beam at the time of a frontal collision can be transmitted quickly to the vehicle body framework so as to enhance the impact absorbing performance. However, whereas this front vehicle body structure can perform stable load absorbing and load transmitting performance with respect to a load applied in a front-rear (or axial) direction of the vehicle body, it can not perform appropriate load absorbing and load transmitting performance with respect to a load applied at an oblique angle to the bumper beam (and hence the impact absorbing sections) because the impact absorbing sections would fall down or collapse due to the obliquely applied load. Collapsing of the impact absorbing sections may be prevented by increasing the wall thickness of the impact absorbing sections. However, increasing the wall thickness of the impact absorbing sections would not only increase rigidity of the impact absorbing sections and thus prevent preferred behavior of the impact absorbing sections, but also increase the weight and manufacturing cost of the front body structure and hence the vehicle.
In the front vehicle body structure disclosed in patent literature 2, the impact absorbing section, provided on each of the left and right sides of the vehicle body, and comprises two (i.e., inner and outer) impact absorbing parts that are provided on the front end surfaces of both the front side frame and the lower frame, and the bumper beam is provided on the front surfaces of these impact absorbing parts. With such two-part impact absorbing sections, this front vehicle body structure can operate effectively by reliably preventing the impact absorbing sections from collapsing against loads input from many directions, particularly against a load input to the bumper beam at an oblique angle relative to the front surface of the bumper beam and hence the impact absorbing sections. However, the impact absorbing sections tend to be complicated in structure. Further, in countries where there are only a few vehicles greater in size than the vehicle employing the aforementioned front vehicle body structure, there is often no particular need to provide the two-part impact absorbing sections in order to secure a great crushing load (energy absorbing amount) of the impact absorbing sections.